Engine



Dec. 9 i925. 1,609,388

A. TEBALDI ENGINE Filed Dec, 5 1921 3 Sheets-Sheet 1 Patented Dec. 7, 1926.

warren stares incense ALESSANDRO TEBALDI, OF MILAN, ITALY.

ENGINE.

Application filed December 5, 1921, Serial No. 520,125, and in Italy December 15, 1920.

The invention relates to a motion transmitting arrangement in engines whereby the effects of the reciprocating masses in the combined cylinder and piston set are 6 obviated for the object of lessening the re-' sistances that are set up in the present piston engines utilizing the expansion of a gas, or to lessen the said resistances in the operating machines working onthe reverse principle (pumps, compressors). The arrangement essentially consists in that the cylinder and piston are pivotally and under neutral equilibrium conditions carried by two parallel shafts, the two shafts being so in terconnected that they turn at the same speed but in opposite directions.

In the accompanying drawings:

Figure 1 shows the arrangement diagrammatically.

Fig. 2 is a horizontal sectional view of a compressed air motor, a motor being shown at the end of its stroke.

Fig. 3 is a longitudinal sectional view taken on line 33 of Fig. 2.

Fig. 4 is a longitudinal sectional view of the combined cylinder and piston set of the motor taken on line &4 in Fig. 3.

Figure 5 is a longitudinal section showing the arrangement as applied to a compressed air motor of modified construction.

Figure 6 diagrammatically shows the arrangement when the cylinder is made stationary. j

Fig. 7 relates to an alternative construction described hereinafter.

In a general way the arrangement. as may be seen from Fig. 1, consists in fixing a piston a to a crank m by means of a rod 1) provided with a counterweight 70, insuch a way .that the pivoting point exactly coincides with the centreof gravity of the system comprising the piston, piston rod and counterweight.

An entirely similar system, in which however the piston is replaced by the cylinder 0 fitted with rod 7), counterweight p and crank m, completes the apparatus. The two cranks m and m revolve in opposite directions about the axis 0 and 0' respectively, arranged such a distance apart that, when the two crank pins g, g respectively,

of cranks m and m are at their maximum distance from one another, the piston playing in the cylinder will have swept the maximum volume, and when the two crank pins are nearest one another, the volume enclosed in the cylinder will be reduced to the minimum (compression chamber or noxious space). In order to obtain a synchronous movement and opposite rotating direction of the two cranks, the two crank shafts 0 and 0' are connected with one another by two gear wheels 6 and '5 equal in diameter or by some other equivalent device.

It will be readily understood that the piston a, piston rod 7) and counterweight 10 constitute a rigid system which, when the apparatus is running, has a single rotary motion about the centre 0 and always remains parallel to itself and in order to maintain it in a given direction, if the motion is a uniform one, no effort is required since it is the question of a solid in a state of indifferent equilibrium becauseof having its center of rotation in its gravity center.

This rotating motion sets up a centrifugal force of constant intensity whosevdirection always coincides withthedirection of the crank.

. This I'centrifugal force can easily be s counterbalanced by "a convenient mass n fitted on the extension of crank g--0.

What has been said regardingthe system made up of piston, piston rod and counterweight applies also to the system consisting of cylinder 0, rod 1) and counterweight p,

the generated centrifugal force being balanced by the mass n. The reciprocating stresses are therefore done away with, which.

in all applications of the combined cylinder and piston are set up by the to and fro-motion of at least one of the said parts; such stresses are generated also in rotary engines and are due to the Coriolis acceleration.

In the application of the invention to a compressed 'air motor as per Figures 2, 3 and 4. capital letters have been used to indicate parts corresponding to those indicated by small letters in Fig. 1.

The piston A -A is double and is re- 10a volved about the shaft 0 by the eccentric M; The are pietcnc slide in the cylinder c o resented by the eccentric M itself'constitutes In fact in the piss. tons A, and A ducts R and R are formed,

the motor distributor.

through which. the. cylinder chambers are set in communication with the recesses S andS formed in the eccentric andv merging intothe ducts'l. andfll formed in: the shaft otthetwo ducts T and T one leadsto thecompressed air reservoir through H, and

the other'to theatmosphere.

As far as-regards balancing, to the cylinder G,G, is fixed the counterweight P servingto bringth'e systems gravity center on the crank, to the shafts O- and O are fixed: the counter-weights NN and N N- servingto balance the centrifugal forces. set up. ,by the cylinder and by the piston.

. Fig-.5 illustrates a modified arrangementofthe compressedair motor to which the above: principle is applied.

In thisarrangement, in order to dispense with the counterweight P. balancing the weight of the cylinder G,C inv the, previously described motor and in order-to thus lessen the engine dimensions, the shaft O has-been made to. coincide with the shaft 0, so that also the rotationaxis of the crank M to which thecylinder C,('] is attached passes through the cylinders gravity centre.

As inthe-en inepreviously described, the double piston K n k is carried by the eccentric M, so. that the two pistons are slid to and froin the cylinders -CC 'carried by the crank M fixed tothe shaft 0.

Also here the eccentric M. fitted to the shaft. O (inconjunction with the connect ing' recesses formedinthe eccentric, with the ducts- R and R and the further ducts-T T in the shaft constitutes the-compressed air distribution system.

The balancing of the centrifugal. force due to the cylinder massis effected by the counterweight N thebalancing of the. centrizfugal force due to the piston. mass is effected by the two counterweights N and N.

On to theshaftsO -O are keyed the gear wheels I and I, which, across suitable intermediate wheels, constrain the two sha lts torevolve at the same angular velocity but in opposite direction.

In. order to obtain a more uniform torque, these motor types may be built up of several motor groups fitted on shafts whose cranks are set atconvenient anglesto one another.

S1m1lar arrangements can be deslgned for the application of the present invention to steam engines, internal combustion engines, pumps, compressors, etc.

If, for instance, constructional requirements involve the necessity of the cylinder being. made stationary instead. of rotatable, the system maintains its characteristic features, provided a suitably arranged counterweight is fitted. In fact it will be seen that the piston in-this'case no longer revolves but receives a harmonic motion, and that the inertia forces set up in the direction of the cylinder axis are exactlyv compensated for by the component, along this same axis, of the centrifugal. force duetothe piston. counterweight- Such-anarrangement, asmayv be seen from, Fig. 6, is entirely similar, to that already; described. The centrifugal. force of the combinationv made up" bythe piston and its'counterweight, is balanced. in the ordinary way bythe counterweightaN.. In .fact. in this case the rotationaxisof thewholesys: tcm will be the pin of thecrank Q, and the supportbywhich theshafts. O and 0 were formerly carried. will, :now work as connect.- ing rod. It appears that,.when thesystem rotates, the axes O and 0, will describe circumferences having, O..-O. for theirradius and: that the rotation centre Q, of. the piston will be rotated bythe-gearwheelsl and I at the samespeed. and. in opposite direction as the poi'ntO, about. Q The composition of the two movementswill constrain: the point Q todisplace itself with a reciprocating motion along thestraight line representing the cylinder axis.

As ultimate result, on examining the motion of thesystem. it will be apparentthat the-point Q, viz, the. supporting. centre: of the pistomrotates about 0 andconsequently the centrifugal force set up. by itiscompensated for by the counterweight N, and the pointO together with the connecting rod 0 -0, revolves about QK thecentrifugalforce set up by the latter system. being balanced by thecounterweight N7 In the same way as in the arrangement previously described,the center 0 may. bemade toroincide with the centre. O and-in such-a case there are only the two=connectingrods Q- O' andQX- O (Fig. 7) and, thelcounterweightsN and N,. p

Having now particularly described the-nature of my 'saidinvention. and what mancomprising two co-axial pistons, two co-axial cylinders n whltch the-.p1stonsfsl1de,.a shaft 1 for said. pistons having an eccentric provided with bores, passageways in the pistons communicating with said-bores andadapted, to lead air into and outrof said cylinders, a

shaft for said cylinders provided with an eccentricengaging the cylinders, gear wheels of substantially equal diameter arranged on centrifugal forces engendered by the pistons said shafts, means connecting said gear and cylinders. Wheels to drive the two shafts in opposite 2. An apparatus as claimed in claim 1 in directions, a counterweight associated with which the shafts are coaxial.

the cylinder shaft to bring the center of Signed at Milan, Italy, this 5th day of gravity of the cylinders on the eccentric of November, 1921.

the cylinders, and other counterweights secured to the piston shaft to balance the ALESSANDRO TEBALDI. 

